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HISTORICAL GEOLOGY 



which more or less resembled the great modern pachyderms 

 such as the elephant and the rhinoceros. They fed upon 

 vegetation, and in spite of their bulk and the formidable 

 array of bony plates, scales, and spines with which many of 

 them were protected, they were probably neither ferocious 

 nor dangerous. There were also smaller and more active 

 reptiles (Fig. 434), which, like the tigers, lions, and other 

 flesh-eating mammal of the present, preyed upon the more 

 sluggish varieties that fed on vegetation. 



FIG. 434. Carnivorous dinosaurs (Allosaurus) of the Jurassic period. 

 (Restored by C. R. Knight, under the direction of Professor Edward D. 

 Cope.) 



Besides the land reptiles, there were batlike forms which 

 had developed the power of flight almost as fully as did some 

 of the birds in later times. These pterosaurs (Fig. 435), or 

 flying dragons, as they are sometimes called, had hollow bones 

 and other characteristics which are now peculiar to the birds. 

 One of them had a spread of wings of more than twenty feet, 

 nearly twice that of the largest living bird but the 

 majority were much smaller. 



